Advanced oxidation of water soluble organics (WSO) from near- and supercritical hydrothermal liquefaction (HTL) of biomass

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Abstract

The challenges involving procuring the necessary water and energy resources for the future generations are partially entwined. An example of the close water-energy dependency is the production of drop-in biofuels by hydrothermal liquefaction (HTL) of biomass in near- and supercritical water. Numerous applications of HTL for conversion of wastes with high water contents (sewage, manure, or lipid-rich algae cultivated on wastewater nutrients) to high-value drop-in biofuels have been studied. The main bulk of the research focuses on the optimization of the biocrude production, while management of the water phase, which contains a large part of the converted biomass (approx. 40 wt.%), is considered a secondary issue. This approach is short-sighted, as an efficient water management, either extraction of the valuables or wastewater treatment, will have to be an integral part of a sustainable HTL in the future biorefineries. In this study, selected advanced oxidation processes (electrochemical oxidation - EO, Fenton oxidation - FO, and supercritical water oxidation - SCWO) were screened to determine their suitability for purification of the aqueous phase produced on a continuous bench scale HTL pilot plant at Aalborg University, Denmark. The effectiveness of each process was evaluated concerning the organic content (TOC and COD) as well as the detailed composition of the samples (GCMS). Chosen process parameters were varied in the experiments (electric current - EO, concentration of H2O2 - FO, and reaction time - SCWO). The results have shown that both WSO and its degradation products, including furans, dioxins, and phenols, are highly toxic. FO was the most efficient method of treatment, but it required significant amounts of chemicals. In EO, no reactants were necessary, but the process depended on a notable energy input. SCWO efficiency was medium, but the process is the most sustainable and thus worth further optimizing.
Original languageEnglish
Publication date11 Sep 2016
Number of pages1
Publication statusPublished - 11 Sep 2016
Event1st International Conference on Sustainable Water Processing - Hotel and Conference Center Melia Sitges, Sitges, Spain
Duration: 11 Sep 201614 Sep 2016
https://www.elsevier.com/events/conferences/international-conference-on-sustainable-water-processing

Conference

Conference1st International Conference on Sustainable Water Processing
LocationHotel and Conference Center Melia Sitges
Country/TerritorySpain
CitySitges
Period11/09/201614/09/2016
Internet address

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